1. Field of the Invention
The invention is in the field of excavating apparatus.
2. Description of the Prior Art
It is known in the art to elevate vehicular tracks to accommodate an auxiliary power means as demonstrated by W. R. Bertelsen, U.S. Pat. No. 3,095,938. M. B. Kurkpatrick, U.S. Pat. No. 2,864,600 teaches a method of employing radially adjustable wheels on a curved platform to guide his mining machine. The prior art does not show a method of primary propulsion on angularly adjustable crawler tracks.
An invention by E. C. Seward, U.S. Pat. No. 3,202,243, although arising out of an entirely different context, teaches two platforms moving relative to one another by means of a piston with both horizontal and vertical capabilities. W. Tiblin, U.S. Pat. No. 3,314,724 employs hydraulic rams to move a main shaft relative to the crawler tracks and H. H. Gardner, U.S. Pat. No. 2,821,374 teaches a pivot actuated steering mechanism which permits vertical movement. The present invention is capable of varying the horizontal, vertical and lateral attitudes of the shaft to fashion a tunnel, and this is new to the art.
W. Tinlin, U.S. Pat. No. 3,314,725 teaches a method of making a rotatable pneumatic drilling head to reciprocate horizontally and vertically within a rectangular frame by means of a plurality of screw jacks. The prior art does not teach a frame mounted movable bearing assembly.
James G. Patrick, U.S. Pat. No. 3,887,236 teaches a tension cutting method wherein undisturbed rock is broken from the inplace mass by a breaking force acting in a radial direction or one otherwise transverse to the direction of excavation dependent upon the cantilevered echelon cut. The prior art does not teach a tension cutting method without the utilization of a cantilevered echelon cut.
L. W. Anderson, U.S. Pat. No. 1,462,997 added to the art the use of rotating pick-up buckets with a central recovery hopper, but nowhere in the art is taught a continuous belt conveyor which rotates with the drilling head. The prior art does not teach a vehicle mounted, kerf cutting and tension wedge breaking drilling head as presented herein.